Python: include Python stack trace in the crash log

This helps Python developers troubleshoot errors when
Python causes a crash.

source/blender/python/generic/py_capi_utils.h

@@ -28,6 +28,7 @@ void PyC_ObSpit(const char *name, PyObject *var);
 void PyC_ObSpitStr(char *result, size_t result_len, PyObject *var);
 void PyC_LineSpit(void);
 void PyC_StackSpit(void);
+void PyC_StackPrint(FILE *fp);
 PyObject *PyC_ExceptionBuffer(void);
 PyObject *PyC_ExceptionBuffer_Simple(void);
 PyObject *PyC_Object_GetAttrStringArgs(PyObject *o, Py_ssize_t n, ...);